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DF: Dielektrische Festkörper

DF 6: Poster

DF 6.13: Poster

Thursday, March 26, 1998, 09:30–12:30, A

Study of the Ferroelectric Phase Transition in DMAAS and DMAGaS single crystals by means of NMR and ESR — •N. Alsabbagh¹, D. Michel¹, J. Furtak², Z. Czapla², G. Völkel¹, R. Böttcher¹, and B. Milsch¹ — ¹University of Leipzig, Faculty of Physics and Geosciences, D-04103 Leipzig, Germany — ²University of Wroclaw, Institute of Experimental Physics, PL-50204 Wroclaw, Poland

Single crystals of dimethylammonium aluminium sulfate (DMAAS) and dimethylammonium gallium sulfate (DMAGaS) were in- vestigated in the ferroelastic and ferroelectric phase by means of quadrupolar perturbed 27Al and 71Ga NMR spectroscopy, respectively. The ferroelectric transition can clearly be inferred from the changes in the NMR spectra. Electron spin resonance (ESR) measurements in chromium doped single crystals demonstrate the order-disorder character of the ferroelectric phase transiton and give information about the critical behavior of the order parameter and the relaxator mode as well.